From: ebiederm-aS9lmoZGLiVWk0Htik3J/w@public•gmane.org (Eric W. Biederman)
To: Gao feng <gaofeng-BthXqXjhjHXQFUHtdCDX3A@public•gmane.org>
Cc: netdev-u79uwXL29TY76Z2rM5mHXA@public•gmane.org,
Linux Containers
<containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public•gmane.org>,
systemd-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public•gmane.org,
davem-fT/PcQaiUtIeIZ0/mPfg9Q@public•gmane.org,
lxc-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public•gmane.org
Subject: Re: [PATCH] netns: unix: only allow to find out unix socket in same net namespace
Date: Tue, 20 Aug 2013 22:30:50 -0700 [thread overview]
Message-ID: <87d2p7vcdx.fsf@xmission.com> (raw)
In-Reply-To: <1377059473-25526-1-git-send-email-gaofeng-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org> (Gao feng's message of "Wed, 21 Aug 2013 12:31:13 +0800")
Gao feng <gaofeng-BthXqXjhjHXQFUHtdCDX3A@public•gmane.org> writes:
> Unix sockets are private resources of net namespace,
> allowing one net namespace to access to other netns's unix
> sockets is meaningless.
Allowing one net namespace to access another netns's unix socket is
deliberate behavior. This is a desired and useful feature, and
only a misconfiguration of visible files would allow this to be a
problem.
> I'm researching a problem about shutdown from container,
> if the cotainer shares the same file /run/systemd/private
> with host, when we run shutdown -h xxx in container, the
> shutdown message will be send to the systemd-shutdownd
> through unix socket /run/systemd/private, and because
> systemd-shutdownd is running in host, so finally, the host
> will become shutdown.
The simple answer is don't do that then. I can see no reason
to share /run outside of the container unless you want this kind of
behavior.
Quite frankly I want this behavior if I am using network namespaces
to support multiple routing contexts. That is if I am using scripts
like:
ip netns add other
ip netns exec other script
I don't want to have to remember to say
ip netns orig exec shutdown -h now
There are more compelling uses and there is no cost in supporting this
in the kernel.
What kind of misconfiguration caused someone to complain about this?
> We should make sure unix sockets are per net namespace to
> avoid this problem.
Nacked-by: "Eric W. Biederman" <ebiederm-aS9lmoZGLiVWk0Htik3J/w@public•gmane.org>
> Signed-off-by: Gao feng <gaofeng-BthXqXjhjHXQFUHtdCDX3A@public•gmane.org>
> ---
> net/unix/af_unix.c | 8 ++++++--
> net/unix/diag.c | 11 ++++++++---
> 2 files changed, 14 insertions(+), 5 deletions(-)
>
> diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
> index c4ce243..98e3689 100644
> --- a/net/unix/af_unix.c
> +++ b/net/unix/af_unix.c
> @@ -295,7 +295,8 @@ static inline struct sock *unix_find_socket_byname(struct net *net,
> return s;
> }
>
> -static struct sock *unix_find_socket_byinode(struct inode *i)
> +static struct sock *unix_find_socket_byinode(struct net *net,
> + struct inode *i)
> {
> struct sock *s;
>
> @@ -304,6 +305,9 @@ static struct sock *unix_find_socket_byinode(struct inode *i)
> &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
> struct dentry *dentry = unix_sk(s)->path.dentry;
>
> + if (!net_eq(sock_net(s), net))
> + continue;
> +
> if (dentry && dentry->d_inode == i) {
> sock_hold(s);
> goto found;
> @@ -784,7 +788,7 @@ static struct sock *unix_find_other(struct net *net,
> err = -ECONNREFUSED;
> if (!S_ISSOCK(inode->i_mode))
> goto put_fail;
> - u = unix_find_socket_byinode(inode);
> + u = unix_find_socket_byinode(net, inode);
> if (!u)
> goto put_fail;
>
> diff --git a/net/unix/diag.c b/net/unix/diag.c
> index d591091..80ada12 100644
> --- a/net/unix/diag.c
> +++ b/net/unix/diag.c
> @@ -218,20 +218,25 @@ done:
> return skb->len;
> }
>
> -static struct sock *unix_lookup_by_ino(int ino)
> +static struct sock *unix_lookup_by_ino(struct net *net, int ino)
> {
> int i;
> struct sock *sk;
>
> spin_lock(&unix_table_lock);
> for (i = 0; i < ARRAY_SIZE(unix_socket_table); i++) {
> - sk_for_each(sk, &unix_socket_table[i])
> + sk_for_each(sk, &unix_socket_table[i]) {
> +
> + if (!net_eq(sock_net(sk), net))
> + continue;
> +
> if (ino == sock_i_ino(sk)) {
> sock_hold(sk);
> spin_unlock(&unix_table_lock);
>
> return sk;
> }
> + }
> }
>
> spin_unlock(&unix_table_lock);
> @@ -251,7 +256,7 @@ static int unix_diag_get_exact(struct sk_buff *in_skb,
> if (req->udiag_ino == 0)
> goto out_nosk;
>
> - sk = unix_lookup_by_ino(req->udiag_ino);
> + sk = unix_lookup_by_ino(net, req->udiag_ino);
> err = -ENOENT;
> if (sk == NULL)
> goto out_nosk;
next prev parent reply other threads:[~2013-08-21 5:30 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-21 4:31 [PATCH] netns: unix: only allow to find out unix socket in same net namespace Gao feng
[not found] ` <1377059473-25526-1-git-send-email-gaofeng-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
2013-08-21 4:58 ` Gao feng
2013-08-21 5:30 ` Eric W. Biederman [this message]
[not found] ` <87d2p7vcdx.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2013-08-21 6:54 ` Gao feng
[not found] ` <5214641C.9030902-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
2013-08-21 7:06 ` Eric W. Biederman
2013-08-21 7:22 ` Gao feng
[not found] ` <52146AC2.5070409-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
2013-08-21 9:51 ` [systemd-devel] " Kay Sievers
[not found] ` <CAPXgP120YUEVnFiD0uPnqeO4x=5oRvHL79-cX5CnmEWc3d5mvQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-08-21 9:56 ` Daniel P. Berrange
2013-08-25 17:16 ` James Bottomley
2013-08-25 17:37 ` Kay Sievers
[not found] ` <CAPXgP115pEE8jxyCqauoMRWui3Qb0fBzPr9L2_SA411=gfnX3w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-08-25 18:16 ` James Bottomley
2013-08-26 1:06 ` Gao feng
[not found] ` <521AAA23.9050604-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
2013-08-26 3:19 ` James Bottomley
2013-08-26 3:35 ` Gao feng
[not found] ` <521ACCEF.4050101-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
2013-08-26 3:53 ` James Bottomley
2013-08-26 13:53 ` Serge Hallyn
2013-08-21 10:42 ` Eric W. Biederman
2013-08-22 1:36 ` Gao feng
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87d2p7vcdx.fsf@xmission.com \
--to=ebiederm-as9lmozglivwk0htik3j/w@public$(echo .)gmane.org \
--cc=containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public$(echo .)gmane.org \
--cc=davem-fT/PcQaiUtIeIZ0/mPfg9Q@public$(echo .)gmane.org \
--cc=gaofeng-BthXqXjhjHXQFUHtdCDX3A@public$(echo .)gmane.org \
--cc=lxc-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public$(echo .)gmane.org \
--cc=netdev-u79uwXL29TY76Z2rM5mHXA@public$(echo .)gmane.org \
--cc=systemd-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public$(echo .)gmane.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox